Venous investigations: the current position.

Chronic venous insufficiency (CVI) is a challenge to the medical profession, for clinical examination provides useful information on CVI, but it is qualitative and does not suffice, especially in patients with isolated deep venous insufficiency but without conspicuous signs of CVI. Ambulatory venous pressure (AVP) measurement has diagnostic value and prognostic capabilities, but it is invasive, is not suitable for repeated use in the same patient, and is not suitable as a screening test. The author surveys noninvasive, volumetric methods that correlate to AVP and that have been developed as alternatives. These include foot volumetry, photoplethysmography, light reflection rheography, ambulatory strain gauge plethysmography, and air plethysmography. The author discusses each with respect to technique, site of measurement, type of exercise used, parameters, correlation to AVP, clinical application, and predictive value. He also describes the tests' ability to determine presence or absence of disease, type of disease, and quantification of disease.